gold/readsyms.cc

   1 // readsyms.cc -- read input file symbols for gold
   2
   3 #include "gold.h"
   4
   5 #include <cstring>
   6
   7 #include "elfcpp.h"
   8 #include "options.h"
   9 #include "dirsearch.h"
  10 #include "readsyms.h"
  11 #include "object.h"
  12
  13 namespace gold
  14 {
  15
  16 // Class read_symbols.
  17
  18 Read_symbols::~Read_symbols()
  19 {
  20   // The this_blocker_ and next_blocker_ pointers are passed on to the
  21   // Add_symbols task.
  22 }
  23
  24 // Return whether a Read_symbols task is runnable.  We need write
  25 // access to the symbol table.  We can read an ordinary input file
  26 // immediately.  For an archive specified using -l, we have to wait
  27 // until the search path is complete.
  28
  29 Task::Is_runnable_type
  30 Read_symbols::is_runnable(Workqueue*)
  31 {
  32   if (this->input_.is_lib() && this->dirpath_.token().is_blocked())
  33     return IS_BLOCKED;
  34
  35   return IS_RUNNABLE;
  36 }
  37
  38 // Return a Task_locker for a Read_symbols task.  We don't need any
  39 // locks here.
  40
  41 Task_locker*
  42 Read_symbols::locks(Workqueue*)
  43 {
  44   return NULL;
  45 }
  46
  47 // Run a Read_symbols task.  This is where we actually read the
  48 // symbols and relocations.
  49
  50 void
  51 Read_symbols::run(Workqueue* workqueue)
  52 {
  53   Input_file* input_file = new Input_file(this->input_);
  54   input_file->open(this->options_, this->dirpath_);
  55
  56   // Read enough of the file to pick up the entire ELF header.
  57
  58   int ehdr_size = elfcpp::Elf_sizes<64>::ehdr_size;
  59   off_t bytes;
  60   const unsigned char* p = input_file->file().get_view(0, ehdr_size, &bytes);
  61   if (bytes >= 4)
  62     {
  63       static unsigned char elfmagic[4] =
  64         {
  65           elfcpp::ELFMAG0, elfcpp::ELFMAG1,
  66           elfcpp::ELFMAG2, elfcpp::ELFMAG3
  67         };
  68       if (memcmp(p, elfmagic, 4) == 0)
  69         {
  70           // This is an ELF object.
  71           Object* obj = make_elf_object(this->input_.name(), input_file, 0,
  72                                         p, bytes);
  73
  74           this->input_objects_->push_back(obj);
  75
  76           Read_symbols_data sd = obj->read_symbols();
  77           workqueue->queue(new Add_symbols(this->symtab_, obj, sd,
  78                                            this->this_blocker_,
  79                                            this->next_blocker_));
  80
  81           // Opening the file locked it, so now we need to unlock it.
  82           input_file->file().unlock();
  83
  84           return;
  85         }
  86     }
  87
  88   // Here we have to handle archives and any other input file
  89   // types we need.
  90   gold_fatal("only objects are currently supported", false);
  91 }
  92
  93 // Class Add_symbols.
  94
  95 Add_symbols::~Add_symbols()
  96 {
  97   if (this->this_blocker_ != NULL)
  98     delete this->this_blocker_;
  99   // next_blocker_ is deleted by the task associated with the next
 100   // input file.
 101 }
 102
 103 // We are blocked by this_blocker_.  We block next_blocker_.  We also
 104 // lock the file.
 105
 106 Task::Is_runnable_type
 107 Add_symbols::is_runnable(Workqueue*)
 108 {
 109   if (this->this_blocker_ != NULL && this->this_blocker_->is_blocked())
 110     return IS_BLOCKED;
 111   if (this->object_->is_locked())
 112     return IS_LOCKED;
 113   return IS_RUNNABLE;
 114 }
 115
 116 class Add_symbols::Add_symbols_locker : public Task_locker
 117 {
 118  public:
 119   Add_symbols_locker(Task_token& token, Workqueue* workqueue,
 120                      Object* object)
 121     : blocker_(token, workqueue), objlock_(*object)
 122   { }
 123
 124  private:
 125   Task_locker_block blocker_;
 126   Task_locker_obj<Object> objlock_;
 127 };
 128
 129 Task_locker*
 130 Add_symbols::locks(Workqueue* workqueue)
 131 {
 132   return new Add_symbols_locker(*this->next_blocker_, workqueue,
 133                                 this->object_);
 134 }
 135
 136 void
 137 Add_symbols::run(Workqueue*)
 138 {
 139   this->object_->add_symbols(this->symtab_, this->sd_);
 140 }
 141
 142 } // End namespace gold.